Detection and mitigation of particle contaminants in MEMS devices

Abstract

Detecting and / or mitigating the presence of particle contaminants in a MEMS device involves including MEMS structures that in normal operation are robust against the presence of particles but which can be made sensitive to that presence during a test mode prior to use, e.g., by switching the impedance of sensitive structures between an exceptionally sensitive condition during test and a normal sensitivity during operation; surrounding sensitive nodes with guard elements that are at the same potential as those nodes during operation, thereby offering protection against bridging particles, but are at a very different potential during test and reveal the particles by their resulting leakage currents; extending the sensitive nodes to interdigitate with or otherwise extend adjacent to the guard structures, which neither contribute to nor detract from the device operation but cover otherwise open areas with detection means during test; and / or converting benign areas in which particles might become trapped undetectably by electric fields during test to field-free regions by extending otherwise non-functional conductive layers so that the particles can then be moved into detection locations by providing some mechanical disturbance.

Description

CROSS-REFERENCE TO RELATED APPLICATION(S)[0001]This patent application claims the benefit of U.S. Provisional Patent Application No. 61 / 253,326 filed Oct. 20, 2009 and also claims the benefit of U.S. Provisional Patent Application No. 61 / 347,863 filed May 25, 2010, each of which is hereby incorporated herein by reference in its entirety.TECHNICAL FIELD[0002]The present invention relates to MEMS device, and more particularly to detection and mitigation of particle contaminants in MEMS devices.BACKGROUND ART[0003]Microelectromechanical system (MEMS) devices are have become established as useful commercial items. One problem that can arise in MEMS devices is that the sizes of micromachined parts are generally comparable with the sizes of airborne dust particles and so the operation of micromachines can be perturbed by dust. In particular, the operation of MEMS devices is susceptible to leakage currents conducted by particles as well as to mechanical interference. Generally speaking, th...

AI Technical Summary

Benefits of technology

This approach allows for effective detection and mitigation of particle contaminants by increasing sensitivity during testing and maintaining operational immunity, thereby improving the reliability and quality of MEMS devices.

Problems solved by technology

One problem that can arise in MEMS devices is that the sizes of micromachined parts are generally comparable with the sizes of airborne dust particles and so the operation of micromachines can be perturbed by dust.

In particular, the operation of MEMS devices is susceptible to leakage currents conducted by particles as well as to mechanical interference.

Generally speaking, the higher the electrical impedance of such systems, the higher is their vulnerability.

In reality, perfect immunity, like perfect cleanliness, is impossible to achieve and must be supplemented.

Images